The Heroes of the Storm website announces that Blizzard plans to open a public test realm for their MOBA next week to help vet the content in The Eternal Conflict update. They provide a FAQ on the process, and the following overview:

The Eternal Conflict will invade the Nexus with our next patch, and we’d like to request your assistance in testing some of the new content and changes it contains before the update arrives on June 30. In order to do this, we’re going to open a Public Test Realm, starting on Tuesday, June 23.

We know many of you will be excited to dive into the new patch content as soon as possible, but we kindly ask that you first take a few moments to check out the access instructions and PTR FAQ below.